83 lines
3.9 KiB
C
83 lines
3.9 KiB
C
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/****************************************************************
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* *
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* Copyright 2001, 2007 Fidelity Information Services, Inc *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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/* lockconst.h - define values used for interlocks */
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#define LOCK_AVAILABLE 0
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#define LOCK_IN_USE 1
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#define REC_UNDER_PROG 2
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/* CAUTION: the following two values are not currently optional on HPUX,
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but rather chosen for HP-PA arthitectural reasons */
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#define GLOBAL_LOCK_AVAILABLE -1
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#define GLOBAL_LOCK_IN_USE 0
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/* Global latch note for platforms with a micro latch (currently Solaris
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and HPUX). The SET_LATCH_GLOBAL macro initializes both the compswap
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lock (major latch) and the micro latch used by compswap. The order this is done in is
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first the micro latch, then the major latch. The order is important so that
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secshr_db_clnup can (re)initialize the entire latch and not run into problems
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with concurrent users attempting to get the lock. The compswap routines in
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these modules will check the value of the major latch first before even attempting
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to obtain the micro latch.
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*/
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#ifdef __hppa
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# define alignedaddr(x) (volatile int *)((UINTPTR_T)(x) + 15 & ~0xf) /* 32-bit */
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/* Given a pointer into memory, round up to the nearest 16-byte boundary
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by adding 15, then masking off the last four bits.
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Assumption: the input address is already int (4-byte) aligned.
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The VOLATILE keyword is essential in this macro: it ensures that the
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compiler does not perform certain optimizations which would compromise
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the integrity the spinlock logic.
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*/
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# define release_spinlock(lockarea) {if (1) { \
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_flush_globals(); \
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(*alignedaddr(&(lockarea)->hp_latch_space) = GLOBAL_LOCK_AVAILABLE); } else ;}
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/* HP white paper sets latch to 1 for available while we set it to -1 */
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/* For performance, release_spinlock is a macro, rather than a function.
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To release or initialize a spinlock, we simply set its value to one.
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We must call the psuedo function "_flush_globals()" to ensure that
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the compiler doesn't hold any externally-visible values in registers
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across the lock release */
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int4 load_and_clear(sm_int_ptr_t);
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# define GET_LATCH_GLOBAL(a) (GLOBAL_LOCK_AVAILABLE == *alignedaddr(&(a)->hp_latch_space) ? \
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load_and_clear((sm_int_ptr_t)&(a)->hp_latch_space) : GLOBAL_LOCK_IN_USE)
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/* above tries a fast pretest before calling load_and_clear to actually
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get the latch */
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# define RELEASE_LATCH_GLOBAL(a) release_spinlock(a)
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# define SET_LATCH_GLOBAL(a, b) {RELEASE_LATCH_GLOBAL(a); assert(LOCK_AVAILABLE == b); SET_LATCH(a, b);}
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#elif defined(__sparc) && defined(SPARCV8_NO_CAS)
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/* For Sun sparc, we use the extra word of the latch for a micro lock for compswap. Future
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iterations of this should make use of the CAS (compare and swap) instruction newly available
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in the Sparc Version 9 instruction set.
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These *_GLOBAL macros are used only from compswap.c (currently)
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*/
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# define GET_LATCH_GLOBAL(a) aswp(&(a)->u.parts.latch_word, GLOBAL_LOCK_IN_USE)
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# define RELEASE_LATCH_GLOBAL(a) aswp(&(a)->u.parts.latch_word, GLOBAL_LOCK_AVAILABLE)
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# define SET_LATCH_GLOBAL(a, b) {SET_LATCH(&(a)->u.parts.latch_word, GLOBAL_LOCK_AVAILABLE); SET_LATCH(a, b);}
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#elif defined(VMS)
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# define SET_LATCH_GLOBAL(a, b) {(a)->u.parts.latch_image_count = 0; SET_LATCH(a, b);}
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#else
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# define SET_LATCH_GLOBAL(a, b) SET_LATCH(a, b)
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#endif
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/* perhaps this should include flush so other CPUs see the change now */
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#define SET_LATCH(a,b) (*((sm_int_ptr_t)a) = b)
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